In the second half of 2011, Google received 6,321 requests that it hand over its users' private data to U.S. government agencies including law enforcement, and complied at least partially with those requests in 93% of cases, according to the latest update to the company's bi-annual Transparency Report that it planned to release Sunday night.

That's up from 5,950 requests in the first half of 2011, and marks a 37% increase in the number of requests over the second half of 2010, when Google received only 4,601 government requests and complied to some degree with 94% of them. And compared with the 3,580 requests for its data it received from U.S. agencies in the second half of 2009, the first time Google released the request numbers, the latest figures represent a 76% spike.

The report's statistics, which Google voluntarily releases, show a steady uptick in government demand for the private information held by the world's biggest Internet firm. The numbers may also point to similar increases in requests for other Internet companies to hand over their users' private data; Google admirably distinguishes itself as the only major Internet company to publicly state how many times agencies have asked for its information. Whether other firms like Facebook, Microsoft, Comcast, AT&T and others have seen a parallel rise in requests can't be determined.

A Google spokesperson I contacted declined to comment on what's driving the rise in requests. But Google policy analyst Dorothy Chou told me in an interview prior to the data's release that one example of the requests might be for the IP addresses of users who log into their Google accounts, which law enforcement agents use to locate individuals involved in criminal cases such as kidnapping.

She says Google requires that the requests come in a written form, come from the appropriate agency, cite a criminal case and are sufficiently narrow in their demands in terms of which users are affected and what time frame of data is requested. "The data can often be very critical to a case," says Chou. "We want to show that we’re advocating on your behalf. But we also want to do right by the spirit and letter of the law.

The U.S. isn't alone in its attempts to nose deeper into Google's servers. Total government requests for users' data from outside the U.S. have also been increasing steadily, spiking sharply to 11,936 in the second half of 2011 compared with 9,600 in the same period last year and 8,959 in the second half of 2009. And the number of foreign requests may be growing even faster than they appear to. Because mutual legal assistance treaties allow some countries to pass on their requests through U.S. government agencies, some portion of those foreign requests are lumped together with the U.S. requests.

Google has a far lower rate of complying with foreign requests, however. It only fulfilled 64% of U.K. requests and 45% of German requests, for instance, and complied with none of the requests from Russia or Turkey.

As well as requests to obtain user data, Google's report also details how many times governments around the world have asked it to remove content from its various services: It received 187 requests to remove 6,192 items in the U.S. in the second half of 2011, up from just 54 requests to remove 1,421 pieces of content in the same period the year before. The report notes that attempts to censor political expression on Google's services are increasing around the world, citing requests that it take down online content from governments that have never made those requests in the past, including Bolivia, Czech Republic, Jordan, Ukraine. A blog post on the report cites requests it removal critical content about government figures even in democracies like Spain and Poland--requests which Google largely denied.

"We noticed that government agencies from different countries would sometimes ask us to remove political content that our users had posted on our services. We hoped this was an aberration. But now we know it’s not," reads the post from Google's Chou. "Just like every other time before, we’ve been asked to take down political speech. It’s alarming not only because free expression is at risk, but because some of these requests come from countries you might not suspect—Western democracies not typically associated with censorship."

By releasing its Transparency Report data, Google at least reveals an issue to the public that would otherwise be debated entirely in the dark. "We have tons of conversations about free expression and privacy, but rarely are they grounded in numbers," says Google's Matt Braithwaite, who leads the engineering team that creates the Transparency Report. "As an engineering company, we want to ground those conversations in numbers. We think it contributes a lot to the public converations we’re having...It’s a starting point. We’d like to continue this conversation with other companies and the public."

Update: A previous version of this story quoted Matt Braithwaite saying that the majority of requests were for users' IP addresses. A Google spokesperson tells me that quote should have been attributed to Dorothy Chou, and that IP address requests are only one example of the requests Google receives, not the majority.